[OpenJDK 2D-Dev] RFR: 8204391: Colors with alpha are painted incorrectly on Linux

[Philip Race]

If Clemens can also look at it, that would be great, but if he does not 
have time
right now, I would not like to hold it up, since its a tck-red for 11.

-phil.

On 7/27/18, 2:27 AM, Jayathirth D V wrote:
> Hi Phil,
>
> Thanks for fixing the regression introduced by https://bugs.openjdk.java.net/browse/JDK-8176795 .
> I went through the changes present in http://cr.openjdk.java.net/~prr/8204931/ and it looks fine.
> I have added detail review summary in the bug itself.
>
> We can also ask Clemens to take a look at the change.
>
> Regards,
> Jay
>
> -----Original Message-----
> From: Phil Race
> Sent: Friday, July 27, 2018 1:12 AM
> To: 2d-dev
> Subject: [OpenJDK 2D-Dev] RFR: 8204391: Colors with alpha are painted incorrectly on Linux
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8204931
> Webrev: http://cr.openjdk.java.net/~prr/8204931/
>
> There is a long evaluation in the bug report, so what I write here is just a summary.
>
> This is a regression introduced by
> https://bugs.openjdk.java.net/browse/JDK-8176795
> and specific to the Xrender pipeline
>
> The bug is that when using colors with alpha, the alpha is being ignored and the colour copied rather than blended, since we no longer pass the "pre-multiplied"
> flag as false.
>
> The fix is to pre-multiply the colour when storing as a pixel even for an opaque xrender surface.
>
> With this fix automated jtreg tests, and tck tests pass, as well as the manual TCK test that was failing.
>
> Additionally the supplied regression test passes on all platforms.
>
> -phil
>
>
>